The U.S. Geological Survey has conducted geologic mapping to characterize the sea floor offshore of Massachusetts. The mapping was carried out using a Simrad Subsea EM 1000 Multibeam Echo Sounder on the Frederick G. Creed on four cruises conducted between 1994 and 1998. The mapping was conducted in cooperation with the National Oceanic and Atmospheric Administration (NOAA) and with support from the Canadian Hydrographic Service and the University of New Brunswick.
The long-term goal of this mapping effort is to produce high-resolution geologic maps and a Geographic Information System (GIS) project that presents images and grids of bathymetry, shaded relief bathymetry, and backscatter intensity data from these surveys that will serve the needs of research, management and the public.

Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.

Attribute_Accuracy_Report: There are no attributes associated with a GeoTIFF image.

Completeness_Report:

The multibeam bathymetric data, on which this image is based, were corrected for tidal elevation during the survey using sea level measured at the NOAA Boston tide gage. This assumes that the tidal elevation and phase are the same as Boston across the survey area. Further processing to correct for the spatial and temporal changes in tidal elevation across the survey area would improve the sounding data and may be undertaken at a later time.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

These data were navigated with a Differential Global Positioning System (DGPS); they are accurate to +/- 3 meters, horizontally.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

These data have been corrected for vessel motion (roll, pitch, heave, yaw) and tidal offsets, and referenced to mean lower low water. The theoretical vertical resolution of the Simrad EM-1000 multibeam echosounder is 1% of water depth; roughly 30 - 50 cm within the study area. However, we found that the working vertical resolution of the system is roughly +/- 50 cm for water depths of 30 - 50 meters based on comparisons of grids from multi-year surveys of the same area.

Image shifted 1/2 grid cell to northwest (using the ArcMap/Data Management Tools/Projections and Transformations/Raster/Shift tool) to correct for an error identified in the SwathEd gridding algorithm in 2007. Correct world file.

Process_Date: 200702

Source_Produced_Citation_Abbreviation: q3_srelief.tif

Source_Produced_Citation_Abbreviation: q3_srelief.tfw

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: William Danforth

Contact_Organization: U.S. Geological Survey

Contact_Position: Operational Geologist

Contact_Address:

Address_Type: mailing and physical address

Address: 384 Woods Hole Road

City: Woods Hole

State_or_Province: MA

Postal_Code: 02543-1598

Country: USA

Contact_Voice_Telephone: (508) 548-8700 x2274

Contact_Facsimile_Telephone: (508) 457-2310

Contact_Electronic_Mail_Address: bdanforth@usgs.gov

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: Pixel

Row_Count: 3442

Column_Count: 3471

Vertical_Count: 1

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: Mercator

Mercator:

Standard_Parallel: 41.650000

Longitude_of_Central_Meridian: -70.316667

False_Easting: 0.000000

False_Northing: 0.000000

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: row and column

Coordinate_Representation:

Abscissa_Resolution: 6.000000

Ordinate_Resolution: 6.000000

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137.000000

Denominator_of_Flattening_Ratio: 298.257222

Entity_and_Attribute_Information:

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Entity_Type:

Entity_Type_Label: Band_1

Attribute:

Attribute_Label: ObjectID

Attribute_Definition: Internal feature number.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain:

Sequential unique whole numbers that are automatically generated.

Attribute:

Attribute_Label: Value

Attribute:

Attribute_Label: Count

Overview_Description:

Distribution_Information:

Distributor:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Bradford Butman

Contact_Organization: U.S. Geological Survey

Contact_Position: Oceanographer

Contact_Address:

Address_Type: mailing and physical address

Address: 384 Woods Hole Road

City: Woods Hole

State_or_Province: Massachusetts

Postal_Code: 02543-1598

Country: USA

Contact_Voice_Telephone: (508) 548-8700 x2212

Contact_Facsimile_Telephone: (508) 457-2309

Contact_Electronic_Mail_Address: bbutman@usgs.gov

Hours_of_Service: 8 a.m. to 5 p.m. EST

Resource_Description: Downloadable Data

Distribution_Liability:

Although these data have been used by the U.S. Geological Survey (USGS), U.S. Department of the Interior (DOI), no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials.
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: TIFF

Format_Specification: GeoTIFF

Format_Information_Content:

A zip archive containing the GeoTIFF image, associated world file, and metadata.

This image is available as a GeoTIFF image with an accompanying world file. To utilize this data, the user must have an image viewer, image processing or GIS software package capable of importing a GeoTIFF image.

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey Information Services

Contact_Address:

Address_Type: mailing address

Address: Box 25286 Denver Federal Center

City: Denver

State_or_Province: Colorado

Postal_Code: 80225-0046

Country: USA

Contact_Voice_Telephone: (303) 202-4700

Contact_Facsimile_Telephone: (303) 202-4188

Hours_of_Service: 8 a.m. to 5 p.m. Mountain Time

Resource_Description: Downloadable Data

Distribution_Liability:

Although these data have been used by the U.S. Geological Survey (USGS), U.S. Department of the Interior (DOI), no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials.
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: TIFF

Format_Specification: GeoTIFF

Format_Information_Content:

A zip archive containing the GeoTIFF image, associated world file, and metadata.

File_Decompression_Technique: zip archive

Transfer_Size: 0.000

Digital_Transfer_Option:

Offline_Option:

Offline_Media: DVD-ROM

Recording_Capacity:

Recording_Density: 4.75

Recording_Density_Units: Gbytes

Recording_Format: UDF

Fees: None

Technical_Prerequisites:

This image is available as a GeoTIFF image with an accompanying world file. To utilize this data, the user must have an image viewer, image processing or GIS software package capable of importing a GeoTIFF image.